I. Field of the Present Invention
The present invention relates generally to apparatus for monitoring the condition of relay switches and more particularly to such an apparatus constructed to automatically transmit a communication signal identifying the change in condition to a remote location through a telecommunication network whenever such a change occurs.
II. Description of the Prior Art
There are many known types of alarm systems. However, previously known alarm systems are often particularly configured for use within a particular environment. As a result, alarm systems used for security purposes often differ substantially from alarm systems used in quality control operations. In particular, the sensors utilized to detect the condition upon which an alarm output must be generated are particularly configured for use with a predetermined environmental structure or a particular function, and thus cannot be employed in other environments
Moreover, the previously known alarm systems often generate alarm output at a location in close proximity to the location at which the condition being sensed occurs. If the alarm output must be provided to a location remote from the location of the condition being sensed, the alarm system typically includes a transmission or communication path between the alarm output and the detector. As a result, expanding the distance between these locations requires the incorporation of a transmission circuit within the alarm system itself, thus substantially increasing the cost and complexity of the alarm system. Moreover, while an installation having dedicated transmission lines may be adequate for communication within a single room or building, it is impractical to employ a dedicated transmission system when the two locations are separated by great distances.
Although telecommunication networks have been established to communicate information over great distances, access to such systems is typically initiated by human operators. In particular, the operator must monitor the initiation of access to a carrier by dialing or instructing an automatic dialer to begin a communication attempt. The operator must also monitor whether a connection with a carrier has been made at the other end or whether a busy signal or other inability to communicate with the remote location prevents transmission of the desired information. If the attempt was frustrated by the inability to obtain a carrier connection with the receiving location, the operator will determine that a second attempt is necessary and reinitiate the communication at a later time. As a result, these previously known alarm systems are not well adapted for use as unattended monitors for alarm conditions arising at one location which must be communicated to a remote location. Therefore, these previously known alarm systems have limited interfacing capacity with telecommunication networks
Although some previously known security systems automatically signal an alarm condition over a telecommunication network, such systems cannot be easily modified to change reported data, accept additional conditions, modify alarm conditions, and change the remote locations to which reports are sent.